Please support download setup-x86_64.exe on IPv6-only network

[Brian Inglis]

On 2023-11-16 03:18, Adam Dinwoodie via Cygwin wrote:
> On Thu, Nov 16, 2023 at 08:13:30AM +0100, Martin Wege via Cygwin wrote:
>> On Thu, Nov 16, 2023 at 2:40 AM Bin W via Cygwin wrote:
>>>
>>> https://www.cygwin.com/setup-x86_64.exe
>>> IPv6-only network can't download the installer.
>>
>> Details please. Does
>> https://www.cygwin.com/setup-x86_64.exe
>> not work on an IPv6-only network?
>>
>> Or can setup-x86_64.exe not download data on an IPv6 network?
> 
> I've just checked: cygwin.com and www.cygwin.com only have DNS A
> records, no AAAA records, so there's no way to get the installer (or
> indeed anything else) from cygwin.com if you're on an IPv6-only network.

There are many other org and ISP issues that could block Cygwin access, like 
A/V, End Point Protection, GPO, firewall, but that may also mean that they do 
not support compatible transitional services and interconnection designed to 
make the difference transparent, possibly except to allowed domains or hosts, 
similarly to depending on insecurity-featuring-obscurity.

> Fixing this will require setting up the web servers for cygwin.com to be
> accessible over IPv6, and configuring the corresponding IPv6 addresses
> in the domain's DNS records.

The whole IP v4 internet is available as a compatibility subnet ::ffff:0:a.b.c.d 
on IP v6, so there is no excuse for not supporting interconnection, as it will 
be required until the last backbone routers drop IP v4 support.

If the OP's org or ISP do not support interconnections to IP v4 hosts, they may 
not have the competence or knowledge to configure and run the appropriate stacks 
and services to support transitional 6over/to4-4over/to6 interconnections, as 
most other hosts and routers on the Internet still do, or it may be policy.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry